Patella Luxation - 6 week old mini poodle?

I require advice as whether a pup I am looking to adopt will have MPL (medial patella luxation). The mini poodle at a 6 week vet check was found to have slight movement in one back leg. The puppy is a papered pedigree and from 40 puppies bred over 4 years from one sire and 2 females, only one has presented with Grade 1 MPL. My pup had same dad but different mum. It is too soon to make a prognosis of MPL? Will x-rays show any congenital deformities at such an early age to exclude MPL? Should I be concerned for the future health and cost to support this pup? If the pup has MPL - 1 will it develop into Grade II, III and IV over the years? Will the dog have to live a limited life devoid of running and jumping? I would appreciate some guidance in this decision.